Many circuit configurations require modules to operate in different voltage domains, i.e., with different supply voltages. In such cases, level shifting circuitry is required to convert signals from one domain to another.
For example, shown in FIG. 1 is a system 100 including a 3.3-5 V power supply 101, a microprocessor (MPU) unit 102 and a peripheral controller 104. The MPU 102 operates at 1.8 V, provided by linear regulator 108. The peripheral controller 104 operates using the supply voltage of 3.3-5 V. Such a peripheral controller may, e.g., be used in a standby mode to perform battery monitoring or ADC (analog-to-digital converter) scans for a capacitive touch sensor (not shown). In such a circuit, the MPU 102 functions as the primary application controller. In order to convert signals from the peripheral controller 104 to be readable by the MPU 102 (and vice versa), level shifting circuitry 106 is required.
In many cases, the development of such level shifting circuitry is time consuming and complex and can cause difficulties in developing microcontroller products.